Dan and Serena are getting locked-up... but not in a sexy hotel room. In Gossip Girl season 6, we learned from TV Line that the former 'Derena' love team will once again get caught in the middle of an 'entrapment', literally.
I can report that producers are planning a callback to the Season 2 episode “The Dark Night” and will once again trap Dan and Serena together in an elevator
Source: TV Line